As evidence of climate change mounts, the urgency increases of transitioning to a low-carbon economy and society. There is a need for greater attention on the countervailing “transition risks” to which the low-carbon transition is likely to give rise. This article defines transition risk and outlines seven categories of such risks. It concludes by calling for more work to assess, evaluate and mitigate these risks, and to develop the tools and methods needed to deal with the systemic interconnections between them.